More on Dynamic Bridles...
| Subject | More on Dynamic Bridles... |
| From | abw@peritas.com (Andy Wardley) |
| Date | Fri, 8 Sep 1995 00:33:29 -1000 |
| Newsgroups | rec.kites |
[ Note: If the crap ASCII-art is too much to handle, check out the Dynamic Bridle page which includes diagrams along with a general discussion on Dynamic Bridles ]
Here, in glorious ascii-colour is a diagram of the dynamic bridle as found on the MEFM ("Infinity Bridle") and others.
a a
\ /
\ /
\ /
\ f g /
c\_____| |_____/e
/ \ / \
/ \ / \
/ \d/ \
/ | \
/ | \
/ T \
b b
In designing a dynamic bridle, your first choice is to decide how long you want it. That is, how far out from the kite does it extend?
A "long"bridle puts less stress on the frame and is less sensitive to adjustment but has increased drag and may get caught around the tail. A shorter bridle is slightly more responsive, can be adjusted to be really wild, has less drag and doesn't have the tangling problems.
At this stage, use extra long lengths anyway. That allows you to lengthen or shorten the bridle to experiment.
Start by tying a piece of bridle line to the centre T-piece connector (point T on the diagram). This should be about 5-10cm (2-4 inches) long (ending at point d). Tie some half-hitch knots along the length of this at even spacing.
T---@---@---@---@---@---@---d
The outer line from the top spreader connector (point a) to the lower spreader connector (point b) should be about 60-100% of the leading edge length, depending on whether you want a short or long bridle. Start long and work down. You need one for each side, obviously.
The centre line (points c -> d -> e) should be about 150-200% of the length of your outer lines. Lark's head this in the middle and slip it onto the T-piece line around one of the knots (point d). You can adjust this later by moving it up or down a knot. Tie loops in the ends of the centre line and lark's head these onto the outside lines at points c and e (you may also want some knots in the outer lines to stop slipping and make adjusting easier).
| | #====f/g | |
The final stage is to lark's head a couple of short pieces onto the centre line to form the tow points, f and g.
Voila!
a a
\ /
\ /
\ /
\ f g /
c\_____| |_____/e
/ \ / \
/ \ / \
/ \d/ \
/ | \
/ | \
/ T \
b b
The diagram here shows the bridle in straight flight, when even pressure is being applied to the tow points. The diagram below shows what happens when the kite turns. Here, the left side is being pulled.
a a
\ /
\ /
\ /
\ g /
c\ |____/e
/\ / \
/ \ f / \
/ \|__d/ \
/ \ \
/ \ \
/ T \
b b
Notice how (if you can understand the ascii-art) the left tow point (f) has moved down and out towards the edge of the kite. This increases the turning speed.
The rules of tuning a dynamic bridle are much the same as a standard bridle. Point c/e moved up the outer line (towards a) make the kite fly faster, in less wind and track better. Moving the points down make it turn more radically. Moving the tow points (f/g) out along the centre line (towards c/e) increase the turning speed but introduce oversteer/tracking problems.
With a dynamic bridle, you need to hold both tow points evenly and look at the angle created by the line from a -> c -> f. If this line is straight, or almost straight, the bridle will be like a static bridle, if this angle is more severe, the bridle will be more dynamic. Look at how the tow points move when you apply even tension and then uneven tension. Too little movement and the bridle will be fairly tame, too much and the kite will get real crazy in turns and probably just fall out of the sky.
A